Lambda supported pipeline for arctic use

ABSTRACT

A stable pipeline in permafrost areas is achieved by supporting pipe on or from supports of lambda construction. The members of the lambda supports extend declivously into solidly frozen permafrost and so maintain a stable line of pipe that will not sink into ground thawed by summer warmth or by heat leakage from the pipeline.

United States Patent Bowers 51 Mar. 14, 1972 154] LAMBDA SUPPORTEDPIPELINE FOR ARCTIC USE [72] Inventor: John R. Bowers, Bartlesville,Okla.

[73] Assignee: Phillips Petroleum Company [22] Filed: Feb. 11, 1970 [21] Appl. No.: 10,455

[52] U.S. Cl ..6l/72.l, 248/49 [51] Int. Cl ..B63b 35/02, F161 1/00, Fl6| 3/00 [58] Field of Search ..248/49, 60, 85, 83, 84, 87; 138/106, 107;6l/72.l

[56] References Cited UNITED STATES PATENTS 1,601 ,571 9/1926 Knapp..24s/49 2,106,956 2/1938 Nakamura ..248/49 2,251,739 8/1941Huntsinger...........................248/6O X 2,579,447 12/1951 Boucher..248/49 2,7365 25 2/1956 Jones 2,780,429 2/1957 Vanier... 2,881,8044/1959 Bub ..248/49 X FOREIGN PATENTS 0R APPLICATIONS 1,227,145 6/1958France 1 38/106 Primary Examiner-Chancellor E. Harris Attorney-Young andQuigg ABSTRACT A stable pipeline in permafrost areas is achieved bysupporting pipe on or from supports of lambda construction. The membersof the lambda supports extend declivously into solidly frozen permafrostand so maintain a stable line of pipe that will not sink into groundthawed by summer warmth or by heat leakage from the pipeline.

14 Claims, 4 Drawing Figures PATENTEUMAR 14 1912 3, 648.468

INVENTOR.

J, R. BOWERS A T TORNE Y5 LAMBDA SUPPORTED PIPELINE FOR ARCTIC USE Myinvention relates to a method of laying a line of pipe within apermafrost area. In another aspect it relates to specially formedsupports to hold a pipeline in a stable position. In a related aspect,the invention involves the movement or transportation of fluids withinarctic regions.

Installing pipelines, particularly large pipelines, within the arcticsnow and permafrost regions presents many problems. The fluids to bemoved in the pipeline are generally warner, sometimes much warmer, thanthe immediate surroundings. Crude oil, for example, is produced in thearctic at about I60" F., and must be maintained above about 30 F. inorder to remain flowable.

There are counterbalancing social and economic forces at work as towhether to bury or not to bury a pipeline within the tundra andpennafrost. The conservationists will desire a line of pipe to be laidon the tundra, utilizing supports such as the unique lambda supports]have devised in my invention, so as to avoid damage or disturbance tothe tundra and hence to the sensitive ecology of the region. Thepipeliners, on the other hand, may want to bury the pipeline in order totake advantage to some extent of the insulating effect of the tundra andpermafrost so as to minimize loss of heat from the pipeline.

The top or surface of the ground in the permafrost country is called thetundra, and is fairly thin, being only about 36 to 40 inches inthickness. It represents the depth of the ground that melts or thaws inthe summer. The depth is somewhat variable, depending on the warmth ofthe summer.

The next layer is the permafrost, and as the term implies it ispermanently frozen, with a temperature reportedly of +l7 to +19 F. Thethickness of the permafrost varies from several feet to half a mole ormore. In some places, this permafrost-or frozen earth contains huge icewedges or frozen buried ice mountains, as well as bodies of dry gravelof varying extent in depth. For the most part, however, the permafrostis a frozen earthlike material. While frozen, the permafrost isexceedingly hard, much harder than ordinary ice of our usual conception,so hard even that it crumples hardened steel when efforts are made toforce steel pilings into the permafrost. Perhaps the untold silentfrozen centuries have slowly changed the ice structure to thisexceedingly hard and resistant material.

The tundra is not something that is lightly disturbed. The tundra actsas an insulator for the pennafrost. If the tundra is removed, and warmweather comes, some of the permafrost melts. Of course, the permafrostmelts if exposed to any source of heat. Once melted, the permafrostloses its amazing strength, and any warm heavy object on or within theper mafrost simply tends to gradually melt its way downward into unknowndepths.

Even well-insulated lines containing warm fluids dissipate some heat totheir surroundings. The pipelines with which we are concerned range fromsmall local fluid transporting or collection lines to 4-foot or greaterdiameter lines capable of moving huge quantities of produced crudeacross the breadth of Alaska, and ultimately across the tremendousbreadth of Canada from northern oil-producing areas down to the warmeroil-consuming regions. These lines must be laid on or in this frozenground. Furthermore, a slight movement of a pipeline can be tolerated,but largely it must be stable. The pipeline must not sink within thepennafrost, nor can heaving upward be permitted in the freeze-thawcycles of the tundra.

My invention uses unique supports of a lambda design. These lambda-formsupports are placed in the permafrost in holes extending declivouslyinto the permanently frozen permafrost beyond the tundra. Thus, myunique lambda supports for my pipeline are permanently held by thepermafrost itself. The pipeline is supported by or slung from the lambdasupports, and so does not depend upon finding any load bearing surfacein or on the ground itself to directly support the pipe. Therefore, anyminor leakage of heat from the line of pipe becomes of littleconsequence. Furthermore, my line of pipe is inherently free of theheaving effects of the tundra.

It is an object of my invention to provide a stable pipeline withinpermafrost areas. An additional object of my invention is to provide aunique method of support of a pipeline so as to minimize one or more ofthe hazards of heaving, sinking, thawing, and/or melting of thepermafrost, insofar as feasible in permafrost country. A further objectis to provide unique supports especially usefiil in arctic areas aspipeline supports.

The supports of my invention are essentially in the form of the Greekletter Lambda, and sol call them lambda supports. The members of thelambda support assembly extend outwardly declivously, i.e., diagonallydownwardly, into permanently frozen permafrost. The upper portions ofthe lambda supports cart be in or above the tundra, the lower portionsof the extending members should be well into the permafrost itself.

The line of pipe itself can be hung from or slung from the lambdasupports by various methods. Tie hangers can be used to connect with agirdle encircling the pipe so as to place the pipe essentially betweenthe lambda support members. booking endwise onto the line of pipe and alambda support, the effect has the appearance of a pendulum. Or, thehanging device can be a loop-type with the tie ends toward the apex ofmy lambda support, and the line of pipe nesting in the lower portion ofthe loop.

The position of the line of pipe itself can be between the members ofthe lambda support and sustained above the ground by means of the lambdasupports. Or, the line of pipe can be more or less laid upon the tundra,or within the tundra, or down toward or on or even within the permafrostlayer. The particular placement will depend on relative convenience, thetopography, and the desired degree of elevation or sunken protectivedepth for the line of pipe. The line of pipe also can be on or at theapex of the lambda support, In fact, my lambda supports can be used tosustain, by which I mean carry or suspend, two or more lines of pipe, ofthe same or different size.

It is expected that some heat will leak from the line. The pipelinecontents, when liquid, will be relatively warm, compared to thesurroundings. While the tundra and the permafrost act as heatinsulators, so that minor heat leakage is not expected to extend farfrom the line of pipe itself, it is expected that there will be a zoneof thaw surrounding the line of pipe, at least to the extent the line ofpipe is buried below the surface. My pipeline, of course, can also beused for the transportation of other fluids, such as gases. In one modeof use of my lambda supports, diagonally laterally extending holes arecut or drilled through the tundra or other overburden down into thepermafrost in an outwardly extending fashion. The vertical diagonalscomprising my lambda supports are placed in these diagonal holes. In oneembodiment the pipeline is run between the diagonals, and hung orsuspended from the apex thereof, by a tie member or sling member, suchas a loop or ring or tie rod or the hanging device. By apex, I refer tothe meeting of the lambda support members.

The line of pipe can be on or above the tundra or other ground surface,in which case no ditching is required, advantageously from aconservation as well as from an economic viewpoint. There would belittle problem in so installing the pipeline during the major portion ofthe year when all of the ground is frozen since the pipeline beinginstalled itself would be at ambient temperature, not containing anywarm fluid. The use of this mode involves minimum disturbance to thetundra, and then only in minor fashion as the holes for the supportmembers are made in the permafrost The line of pipe itself can be placedvarious depths downward, either by varying the length of the hangingdevices, or by other methods. The overburden can be removed in part,including tundra and also permafrost where necessary, and the line ofpipe hung or suspended downwardly, and the overburden replaced.

Another embodiment of my invention has the appearance of one lambdainverted on another lambda, where the extending members of the supportare sufficiently long as to meet and pass each other, so to speak,extending upwardly and outwardly beyond each other. The pipeline is hungbelow the cross-point of the supports, or rests along the cross-points,or aptces.

It also is within the conception of my invention to install these lambdasupports and equip them with an apex device, such as a semicircularsaddle, so that the line of pipe can rest along the centers of thelambda supports on such pipe-saddles.

Referring, now, to my drawing attached, the several figures show variousaspects of my invention and the main alternative ways of employing myinvention.

FIG. 1 shows the pipeline installed with the members of my lambdasupports extending outwardly downwardly into the permafrost.

In FIG. 2 the pipe is partially in tundra and partially in permafrost.

In FIG. 3 the pipe is supported by the apex of the lambda support, thewhole asembly being covered with backfill.

In FIG. 4 a line of pipe is suspended between the support members and inthe tundra, while another line of pipe or conduit is supported at theapex of the support members, and above the ground surface.

For installation of the supports, declivously extending holes can bedrilled, cut, steam-lanced, or otherwise formed through the tundraoverburden down into the permanently frozen permafrost. The lambda framemembers can then be inserted, and the permafrost allowed to refreeze,such as by adding water around the frame member bottom portions ifnecessary. Once refrozen, the permafrost will stay that way unless againsubjected to excessive quantities of heat.

Referring now to FIG. I with more detail, the overburden or tundra l isshown as the upper layer of the arctic ground, and below that thepermafrost 2. Diagonally downwardly extending holes are formed into thepermafrost 2. Into these holes are inserted the members 3 and 4 of thelambda support. These supports will normally form an apex S. From theapex 5 the pipe 6 can be hung, slung, or otherwise held or maintained orsupported in place. In PK]. 1 a pipe hanging device, loop or sling 7,such a a wire rope, is shown holding the pipe more or less at the groundsurface.

FIG. 2 illustrates an embodiment similar to FIG. I. The line of pipe isshown partially in the tundra l and partially in the permafrost 2. Thepipe hanging device 7 here is shown holding a loop or ring or girdle 8through which the pipe 6 is run.

FIG. 3 illustrates an embodiment wherein the members of the lambdasupport meet with a pipe-holding configuration or pipe-guide 9, such asa saddle, The line if pipe 6 can be laid along the saddles 9 of thelambda support members.

in FIG. 4 my invention is illustrated showing the lambda support members3 and 4 meeting and forming a saddle 9 or a similar support for an upperline of pipe 6 or other type of conduit, with the upper line 6 laid onor along the supports 9 and above the tundra l. A lower line of pipe 6is shown hung or slung by a suspending device 7 between the lambdasupports 3 and 4. The embodiment shown illustrates one line of pipeabove the surface, another line of pipe within the tundra. Of course,both pipes can be above the tundra, one above and one in the tundra,both in the tundra, one on or in the tundra and one on or in thepermafrost, or otherwise as desired, even closely adjacent alongside of,or above and below, each other.

Utilization of my supports to carry two lines of pipe is par ticularlyhelpful in some areas by virtue of the fact that one pipeline can begrossly different in size as opposed to the other pipeline. For example,one line of pipe can be very large carrying the primary fluid beingtransported, a second line of pipe then is supported along, below orabove the major pipeline, more or less in close proximity thereto,carrying a tracing or heating fluid such as steam. Or, the one line canbe a fluid pipeline, the other line a cable line, tube, or similarconduit for communications and the like.

My lambda supports, with the lower diagonally downwardly extendingmembers thereof extending well into the permanently frozen permafrost,form a stable pipeline suspending support method not subject to thevague unease of the tundra in its freeze-thaw cycles. At the same time,my device permits the pipeline itself to have a degree of freedom ofmovement as the tundra heaves slightly from winter to summer. As slightground movements occur, the pipeline itself in a sense will be freelyhangs so that it can move slightly and avoid being torn apart by theotherwise high stresses induced by the freezethaw cycles of the tundraand permafrost.

The lambda support members can be of various cross-sectional shapes orconfigurations, depending on the manner of placement, the method bywhich a position for the support is formed, or the type of material ofconstruction involved or available. The support members can beessentially round or cylindrical, square, rectangular, oval, and thelike. It is to be expected that the members usually will be solid,though hollow construction is useful in some applications, such as forsmaller pipes with smaller loads. A tubular or slip-tube sectionalconstruction with holding pin is helpful in some situations.Configuration also is influenced by factors of heat conduction, as wellas factors of materials availability. The pipe guides can be an integralpart of the lambda supports, or can be a separate structural member ofthe overall lambda support.

The requirements for materials of construction primarily are strength tosupport the load of the pipeline, generally unaffected by wide rangingchanges of temperature, and preferably minimally affected by varyingexposure to water. Metal laterals and supports or combinations of metaland other materials can be utilized.

The nonheat conducting properties and high strength properties of someplastic materials will be useful, where such are available in suitablequantity and cost. Wood is basically suitable, though often not readilyavailable in much of the arctic area. Concrete, particularly reinforcedconcrete, or even ceramic materials ofvarious types, are useful.

No one method of installing my pipeline and supports will be suitablefor its entire length. The variations of my pipeline and supports willbe useful in various areas, depending upon the general temperatures, thethickness of the tundra overburden, presence of permafrost itself orwhether a dry gravel stretch may be involved, and the like. My lambdasupports provide particular flexibility in meeting varying topographyand other conditions, and further provide an unusually versatileapproach to pipeline laying, or hanging if you prefer, in arcticregions.

Reasonable variations and modifications of my invention are possiblewithin the scope of my disclosure yet without departing from the scopeand spirit thereof as l have disclosed in the specification hereinaboveand the claims hereinafter.

lclaim:

l. A pipeline assembly comprising in combination:

a. a series of spaced lam bda-shaped supports, each support including apair of vertically diverging members with the lower extending ends ofeach member of said supports installed in a diagonally outwardlydownwardly extending hole in the ground, said ground comprising tundraand permafrost, and said lower extending ends extending into permanentlyfrozen permafrost beyond a depth subject to seasonal freeze-thaw andfurthermore beyond area subject to heat-introduced thaw, each pair ofsaid spaced supports essentially converging at the upper extending endsof the members thereof and thereby forming said lambda-shaped supports,

b. means for sustaining a substantially rigid closed tubular pipeline,

c. at least one substantially rigid closed tubular pipeline stablysustained by said series of said lambda supports.

2. A pipeline assembly according to claim I wherein said pipeline hangsfrom said upper extending ends and between said members of said lambdasupports.

3. A pipeline assembly according to claim 2 further including a pipesuspending device selected from at least one of a loop, ring, sling, andtie rod.

4. A pipeline assembly according to claim 1 wherein said spaced supportssupport said pipeline on said upper extending ends of said lambdasupports.

5. A pipeline assembly according to claim 4 wherein a plurality of saidlambda supports include on the upper extending ends thereof pipe-saddlesand said pipeline lies on said pipesaddles.

6. A pipeline assembly according to claim I wherein said lambda supportssustain at least two pipelines.

7. A pipeline assembly as a stable conduit for the movement of warmfluids in areas subject to permafrost, said pipeline assembly comprisingin conjunction a pipeline and a support assembly therefor, said supportassembly comprising a series of spaced support members constructed ofsubstantially nonheat conducting materials and installed so as tosustain said at least one pipeline, each said support assemblyessentially in the form of a lambda, and said spaced support membersextending declivously relative to said at least one pipeline into saidpermafrost and beyond a zone of thaw induced by at least one of summerheat and heat release from said warm fluids contained in said pipeline.

8. A pipeline assembly according to claim 7 further including a secondpipeline laid upon and along the upper extending ends of said supportassembly.

9. A method for laying a pipeline for the transport of warm fluids inthe arctic area which comprises a. cutting a series of opposingly placeddownwardly extending holes in the ground in said arctic area, saidground comprising tundra and pennafrost, said holes extendingdeclivously through the depths subject to seasonal freezethaw and intosaid permafrost beyond a zone of thaw induced by heat leakage from saidwarm fluids in said pipeline,

b. installing in each of said declivously extending holes a supportmember such that each pair of opposingly positioned spaced declivouslyextending supports comprise and form a lambda support,

c. sustaining at least one pipeline along said lambda supports.

10. The method according to claim 9 wherein in said step (c) saidpipeline is sustained by the apices formed by the series of lambdasupports.

11. The method according to claim 10 wherein a plurality of said lambdasupport members have a pipe saddle positioned at the apex of each pairof support members forming said lambda supports, and said pipeline issustained along said pipe saddles.

12. The method according to claim 11 wherein said at least one pipelineis laid along said guide collars and a further pipeline is suspendedfrom the apices of said lambda supports.

13. The method according to claim 10 wherein at least one of saidpipelines is covered with backfill.

14. The method according to claim 10 wherein at least one said pipelineis further characterized as being insulated.

1. A pipeline assembly comprising in combination: a. a series of spacedlambda-shaped supports, each support including a pair of verticallydiverging members with the lower extending ends of each member of saidsupports installed in a diagonally outwardly downwardly extending holein the ground, said ground comprising tundra and permafrost, and saidlower extending ends extending into permanently frozen permafrost beyonda depth subject to seasonal freeze-thaw and furthermore beyond areasubject to heat-introduced thaw, each pair of said spaced supportsessentially converging at the upper extending ends of the membersthereof and thereby forming said lambdashaped supports, b. means forsustaining a substantially rigid closed tubular pipeline, c. at leastone substantially rigid closed tubular pipeline stably sustained by saidseries of said lambda supports.
 2. A pipeline assembly according toclaim 1 wherein said pipeline hangs from said upper extending ends andbetween said members of said lambda supports.
 3. A pipeline assemblyaccording to claim 2 further including a pipe suspending device selectedfrom at least one of a loop, ring, sling, and tie rod.
 4. A pipelineassembly according to claim 1 wherein said spaced supports support saidpipeline on said upper extending ends of said lambda supports.
 5. Apipeline assembly according to claim 4 wherein a plurality of saidlambda supports include on the upper extending ends thereof pipe-saddlesand said pipeline lies on said pipe-saddles.
 6. A pipeline assemblyaccording to claim 1 wherein said lambda supports sustain at least twopipelines.
 7. A pipeline assembly as a stable conduit for the movementof warm fluids in areas subject to permafrost, said pipeline assemblycomprising in conjunction a pipeline and a support assembly therefor,said support assembly comprising a series of spaced support membersconstructed of substantially nonheat conducting materials and installedso as to sustain said at least one pipeline, each said support assemblyessentially in the form of a lambda, and said spaced support membersextending declivously relative to said at least one pipeline into saidpermafrost and beyond a zone of thaw induced by at least one of summerheat and heat release from said warm fluids contained in said pipeline.8. A pipeline assembly according to claim 7 further including a secondpipeline laid upon and along the upper extending ends of said supportassembly.
 9. A method for laying a pipeline for the transport of warmfluids in the arctic area which comprises a. cutting a series ofopposingly placed downwardly extending holes in the ground in saidarctic area, said ground comprising tundra and permafrost, said holesextending declivously through the depths subject to seasonal freeze-thawand into said permafrost beyond a zone of thaw induced by heat leakagefrom said warm fluids in said pipeline, b. installing in each of saiddeclivously extending holes a support member such that each pair ofopposingly positioned spaced declivously extending supports comprise andform a lambda support, c. sustaining at least one pipeline along saidlambda supports.
 10. The method according to claim 9 wherein in saidstep (c) said pipeline is sustained by the apices formed by the seriesof lambda supports.
 11. The method according to claim 10 wherein aplurality of said lambda support members have a pipe saddle positionedat the apex of each pair of support members forming said lambdasupports, and said pipeline is sustained along said pipe saddles. 12.The method according to claim 11 wherein said at least one pipeline islaid along said guide collars and a further pipeline is suspended fromthe apices of said lambda supports.
 13. The method according to claim 10wherein at least one of said pipelines is covered with backfill.
 14. Themethod according to claim 10 wherein at least one said pipeline isfurther characterized as being insulated.